Gill proteome networks explain salinity tolerance of Oreochromis mossambicus

Acclimations of Oreochromis mossambicus to elevated salinity were conducted with multiple rates of salinity increase and duration of exposure to determine the rate-independent maximum salinity limit and the incipient lethal salinity. A data-independent acquisition (DIA) assay library was created for quantitative analysis of over 3000 gill proteins simultaneously in treatments representative of important key zones in the salinity level/duration landscape. From these DIA data, protein networks that represent complex molecular phenotypes associated with salinity acclimation were generated. Acclimations of Oreochromis mossambicus to elevated salinity were conducted with multiple rates of salinity increase and duration of exposure to determine the rate-independent maximum salinity limit and the incipient lethal salinity. A data-independent acquisition (DIA) assay library was created for quantitative analysis of over 3000 gill proteins simultaneously in treatments representative of important key zones in the salinity level/duration landscape. From these DIA data, protein networks that represent complex molecular phenotypes associated with salinity acclimation were generated. Protein fold change (FC) and organismal level performance indicators of salinity tolerance were then correlated. Gill protein networks impacted at extreme salinity levels both above and below the incipient lethal limit include increased energy metabolism, especially upregulation of electron transport chain complex proteins, and significant downregulation of a previously uncharacterized protein which bears strong amino acid sequence similarity to fucolectin. Proteins networks strongly impacted by crossing into the zone of resistance include cell adhesion and extracellular matrix regulation.

本研究以莫桑比克罗非鱼（Oreochromis mossambicus）为实验材料，通过设置多组盐度升高速率与暴露时长梯度开展高盐驯化实验，以确定与速率无关的最大盐度耐受极限及初始致死盐度。我们构建了数据非依赖采集（data-independent acquisition, DIA）分析文库，可同时对盐度水平-暴露时长梯度关键代表性处理组中的3000余种鳃组织蛋白进行定量分析，并基于该DIA数据构建了与盐度驯化相关的复杂分子表型对应的蛋白调控网络。随后，我们将蛋白丰度倍数变化（fold change, FC）与机体盐度耐受的整体性能指标进行相关性分析。在初始致死盐度上下的极端盐度条件下，受影响的鳃组织蛋白网络涉及能量代谢增强，尤其是电子传递链复合物蛋白的表达上调；同时，一种此前未被表征、氨基酸序列与岩藻凝集素（fucolectin）高度相似的蛋白被显著下调。当生物体突破盐度耐受阈值进入抗性受限区域时，细胞黏附与细胞外基质调控相关的蛋白网络会受到显著影响。